Duplex tube



June 19, 1956 E. G. DORGELO DUPLEX TUBE Filed Aug. 6, 1955 INVENTOR gifduard Gerhards/s D07 GIO United States Patent O DUPLEX TUBE EduardGerhardns Dorgelo, Eindhoven, Netherlands, as-

signor to Hartford National Bank and Trust Company, Hartford, Colm., astrustee Application August 6, 1953, Serial No. 372,726

Claims priority, application Netherlands September 2, 1952 2 Claims.(Cl. 315-39) The invention relates to electric discharge tubes in whichtwo semi-cylindrical grids, a common screen grid and twosemi-cylindrical anodes are arranged to surround a common cathode.

The anodes of such tubes are frequently supported from lead-in studs.However, if very short waves, meter and decimeter waves, are used, thetubes have a limitation in that the losses in the comparatively thinlead-in studs greatly increase with the frequency. However, increasingthe thickness of the lead-in studs entails structural difficulties.

According to the invention, in an electric discharge tube in which twosemi-cylindrical grids, a common screen grid and two semi-cylindricalanodes are arranged to surround a common cathode, the anodes are unitedat the non-supported end of the other electrodes so as to form acylinder open at one end which for the greater part of its lengthcomprises two diametrically opposed cuts, the anodes being supportedfrom a conductive cylinder of smaller diameter, sealed directly into thetub wall and enclosing an axial conductor which, within the spaceenclosed by the anodes, merges into a coupling loop.

When the tube is to be operated, the only thing required is to connectthe external circuit to the axial conductor formed by the cylinder andits internal conductor. The coupling loop and the axial conductor may beproportioned such that the external load circuit conforms to theimpedance of the anode system.

Since the anode is supported from a cylinder it is possible for thethermal conduction to reach an adequate value. lf required, thecylindrical conductor may be additionally cooled without the tube.

The invention will now be described with reference to the accompanyingdiagrammatic drawing, in which:

Figs. l and 2 are cross-sectional views of a duplex tube according tothe invention taken parallel to and at right angles to its axisrespectively.

Referring now to the figures, a glass tube wall 1 has a base 2. The base2 has several studs 3 sealed into it 2,751,521 Patented June 19, 1956upon which are supported an indirectly heated cathode 4 and twosemi-rod-grids 5.

Upon a at disc 6 sealed in the wall is supported through a cone 7 ascreen grid 8 which also consists of rods. The anodes form a cylinder 9in which wide sawcuts 10 are formed. The anode 9, which is made ofmolybdenum, is soldered to a ferro-chromium cylinder 11 which isinternally coated with a layer of copper 12. An internal conductor 13merges into a coupling loop 14 within the anode cylinder.

Some few cooling lns provided on the ferro-chromium cylinder 11 aredesignated 15.

What is claimed is:

l. An electric discharge tube comprising an envelope, an electrodesystem disposed in said envelope, said electrode system including acommon cathode, two semicylindrical grids, a common screen grid and ananode mounted in that order, means supporting said cathode and grids atone end, said anode comprising a cylinder of given diameter open at oneend and including a pair of diametrically-opposed slots extending fromthe open end of said cylinder toward the other end, a conductivecylinder of diameter smaller than said given diameter sealed directly insaid envelope, said conductive cylinder supporting said anode, an axialconductor extending through said conductive cylinder, and means couplingsaid axial conductor to the space enclosed by the anode.

2. An electric discharge tube comprising a vitreous envelope, anelectrode system disposed in said envelope and including a commoncathode, two semi-cylindrical grids, a common screen grid and an anodemounted in that order and surrounding one another, means at one end ofsaid envelope supporting said cathode and grids at the end adjacent saidone end, said anode comprising a cylinder of given diameter open at oneend and including a pair of diametri'cally-opposed slots extending fromthe open end of said cylinder substantially toward the other endthereof, said open end of said anode cylinder facing said one end ofsaid envelope, said slots deiining two semi-cylindrical anode portionsaligned with said two semi-cylindrical grids, a conductive cylinder ofdiameter smaller than said given diameter sealed directly in the otherend of said envelope and secured to and supporting said anode cylinderat its other end, an axial conductor extending lengthwise through saidconductive cylinder, and a coupling loop connected to said conductor anddisposed within a portion of the space dened by the anode cylinder.

References Cited in the le of this patent UNITED STATES PATENTS2,351,744 Chevigny .lune 20, 1944 2,423,819 Chevigny July 8, 19472,466,063 Varian Apr. 5, 1949

